For connecting microcontrollers to peripheral devices several protocols are known, e.g., SENT, PSI5, PSI5s, I2S, SPI, ASC, LIN, serial radar LVDS interface. It is also known that microcontrollers compromise for the implemented protocols one or more protocol IP modules. In order to test the IP modules either during production or, for example, under extreme temperature conditions (so called reliability testing), the testing infrastructure uses either internal loopback mechanism (if supported by the respective IP module) or some sort of waveform generator generating basic protocol frames. The created protocol frames are usually limited with respect to their scope.
Another aspect of microcontroller's functionality are safety mechanisms for detecting protocol errors (CRC/parity error, framing error, encoding error, etc) in data signals. The safety mechanisms are to be checked during the production of the microcontrollers and even customers need to check the safety mechanisms in a startup phase before enabling safety features on the microcontroller. For testing the safety mechanisms, it is known to use external components for submitting erroneous signals to the microcontroller. This is hardly a feasible option for the end user.